Method and circuit for improving device power up timing and predictability

Abstract

Method and system for controllably and sequentially powering up subsystems of an electronic system, device or integrated circuit. In one example, a first supply voltage is selectively applied to a first subsystem, and when the first supply voltage has reached a predetermined value, a second supply voltage is selectively applied to the second subsystem. The first and second supply voltages may also be boosted to provide fast startup timing. In this manner, the first subsystem is powered-up before the second supply voltage is applied to the second subsystem—this provides for controlled, sequential power up of the subsystems of the electronic system, device or integrated circuit.

Description

CROSS REFERENCE TO RELATED APPLICATION [0001] This application claims priority under 35 U.S.C. 119(e) to U.S. provisional patent application Ser. No. 60 / 556,968 filed Mar. 26, 2004 and entitled “Method of Improving Device Power Up Timing and Predictability,” the disclosure of which is hereby incorporated by reference in its entirety.FIELD OF THE INVENTION [0002] This invention relates, in general, to electronic circuits, and in particular to circuits for controlling power in an integrated circuit or electronic system. BACKGROUND OF THE INVENTION [0003] Many devices or systems, particularly those using low voltages and consuming low power, require a voltage regulator, either internal or external, that provides a regulated supply voltage. Low voltage regulators are frequently used in low voltage or low power devices. Typically, an output of a voltage regulator is applied to the entire device or system, which can cause some drawbacks. A first drawback is that power up speed of the devi...

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Benefits of technology

[0017] According to another embodiment, a method is disclosed for providing predictable power-up sequences for a device or system, in accordance with an embodiment of the present invention, which can be used for sta

Problems solved by technology

Typically, an output of a voltage regulator is applied to the entire device or system, which can cause some drawbacks.

A first drawback is that power up speed of the device or system may be limited by the performance/specifications of the voltage regulator.

A second drawback is that the device or system which uses the voltage regulator may have many sub-blocks, and once the regulato

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